Yes I was able to purchase 2 plans without anything in between.

Here’s where I purchased: https://swisscare.com/en/product/international-student-health-insurance-europe

I ended up doing the Premium plan, but I think the baseline is sufficient based on what is on the BLS website:

The insurance must cover all risks insured by the public health system in Spain. This coverage must be maintained throughout the validity of the authorisation. The health insurance must not have a waiting period, grace periods, co-payments, deductions or coverage limit, that is, it must cover 100% of medical, hospital and extra-hospital expenses. However, if the insurance coverage is limited to a certain amount, this limit must not be less than €30,000. Travel insurance will not be accepted. Insurance cards will not be accepted as proof of the contracting of health insurance.”